1. Field of the Invention
This invention relates to a reflective light emitting diode (LED) having a reflective surface that reflects the light emitted from a reflective optical device, namely an LED element, thereby obtaining high external radiation efficiency. The invention also relates to a photodetector such as a reflective photodiode or a reflective phototransistor having a reflective surface that condenses and receives the light entering from an outside, thereby obtaining high photo-detecting rate. The invention also relates to a reflective photo-detecting/light-emitting device or the like having a pair of the LED and the photodetector. Hereafter, the reflective light emitting diode is referred to simply as xe2x80x9creflective LED.xe2x80x9d The reflective photodiode is referred to simply as xe2x80x9creflective PD.xe2x80x9d The reflective phototransistor is referred to simply as xe2x80x9creflective PT.xe2x80x9d
In the specification, the LED chip itself is referred to as xe2x80x9cLED element,xe2x80x9d while an entire light emitting device including a sealing resin to mount an LED chip and an optical device such as a lens system, is referred to as xe2x80x9clight emitting diodexe2x80x9d or xe2x80x9cLED.xe2x80x9d In the same manner, the PD chip or PT chip itself is referred to as xe2x80x9cphoto-detecting element,xe2x80x9d while an entire photo-detecting device including a sealing resin to mount a PD chip or PT chip and an optical device such as a lens system, is referred to as xe2x80x9cphotodiodexe2x80x9d or xe2x80x9cPDxe2x80x9d or xe2x80x9cphototransistorxe2x80x9d or xe2x80x9cPT.xe2x80x9d The LED element, the photo-detecting element and the photo-detecting/light-emitting element combining them are referred to as xe2x80x9csolid-state optical element.xe2x80x9d
2. Description of the Related Art
A reflective light emitting diode (reflective LED) is known conventionally. The reflective LED has a lead mounting an LED element thereon. The lead and the LED element is sealed with a synthetic resin. A reflective surface shape is formed by molding at a light-emitting surface side of the LED element, while a radiation surface shape is formed by molding at a rear surface side of the LED element. Then, a reflective mirror is formed by evaporation of a metal such as a silver on a synthetic resin surface of the reflective surface shape.
As an example of such reflective LED, an LED is shown in FIG. 35 and FIG. 36 which is disclosed in Japanese Laid Open Patent Publication (Kokai) 10-144966. FIG. 35 is a plan view of an entire configuration of a conventional reflective LED. FIG. 36 is a cross-section taken along the line XXXVIxe2x80x94XXXVI of FIG. 35.
As shown in FIG. 35 and FIG. 36, a reflective LED 331 has a pair of leads 333a and 333b. An LED element 332 is mounted on a lower surface of the one lead 333a. A wire 334 bonds and electrically connects the other lead 333b and the LED element 332. Thus structured lead portion is encapsulated by a transparent epoxy resin 336 to form a molded shape. The molded shape has a radiation surface shape 336a at a rear surface side of the LED element 332 and a reflection surface shape 336b at a light emitting surface side of the LED element 332. A silver is vapor-deposited on the reflection surface shape 336b to form a reflection mirror 335.
In such structure of the reflective LED 331, external radiant efficiency does not decrease as in a lens LED even if a light-condensing rate is increased. The LED 331 can obtain high external radiation property, which does not depend on light distribution property, by the reflection mirror 335 having a solid angle of about 2xcfx80 steradian in relation to the LED element 332. Therefore, the LED 331 has less dislocation of an axis and is particularly suitable for light-condensation/external-radiation. Moreover, the upper and lower optical surfaces can be easily shaped at the same time by a transfer mold. Therefore, the LED 331 is suitable for mass production, too. There have been many propositions about a structure of the reflective LED. Still, it is only such transfer molding type LED that can be mass-produced and that are actually supplied to a market.
However, the reflective LED 331 is adversely affected by temperature change, since coefficient of thermal expansion is very much different between the sealing resin and the vapor-deposited metal. Moreover, the LED 331 is structurally weak and subject to separation or delamination. Then, the metal material of the reflection mirror 335 may be peeled off from the sealing resin 336, thereby causing wrinkles on the reflection surface. Thus, the LED loses a function of the reflection mirror. Therefore, the LED 331 cannot deal with a process in a reflow furnace or the like for mounting substrates in which large temperature change takes place. Thus, there is a problem that the LED 331 cannot be surface-mounted.
Furthermore, as shown in FIG. 35, lead extracting portions 337a, 337b of 1 to 1.5 mm long must be formed on the sealing resin 335 for providing a masking space to prevent short-circuit of the leads 333a, 333b at the time of vapor-deposition of the metal and for reinforcement of end portions at the time of perpendicularly bending the leads 333a, 333b. Therefore, a package of the reflective LED 331 needs extra dimension of 2 to 3 mm. Consequently, another problem arises that there is a limit in miniaturization and high-density mounting.
In addition, the LED requires higher heat radiation property. This is because, in general, if temperature of the LED element increases, a light output of the LED element decreases, and its life property deteriorates, too. Particularly, in case large current is conducted to the LED element, an active heat radiation property is needed. Therefore, the heat radiation property has been insufficient in the conventional reflective LED that has such a structure as the LED 331.
The reflective LED 331 by the transfer molding uses a synthetic resin having large fluidity. Therefore, a metal mold requires high accuracy and it has been difficult to fabricate the metal mold. Moreover, it has been necessary to fabricate a metal mold for each of LEDs having different specification of light distribution. Furthermore, there is a problem that a kind of usable sealing resin is limited and that the sealing resin is easily yellowed thereby shortening the life particularly of a blue LED.
An object of the present invention is to provide a reflective optical device that has durability against a temperature change, that is easy to be miniatured and that is excellent in heat radiation.
Another object of the present invention is to provide a reflective optical device such as a reflective LED and its manufacturing method that has high light condensation/radiation efficiency and little dislocation of an axis, that has durability against a temperature change, that has many choices of encapsulating materials to be used and that is excellent in mass-productivity.
Still another object of the present invention is to provide a reflective optical device such as a reflective LED and its manufacturing method that has high light condensation/radiation efficiency and little dislocation of an axis, that has durability against a temperature change and a physical contact so as to be surface-mounted, that is easy to be miniatured, that can change a light distribution without a new metal mold and that is excellent in mass-productivity.
According to a first aspect of the invention, there is provided a reflective light emitting diode (LED). The LED comprises: an LED element; a pair of leads for supplying an electric power to the LED element; a reflection mirror of concave shape facing a light emitting side of the LED element; and a radiation portion provided at a back side of the LED element. The LED element is mounted on one of the leads. The one of the leads is contacted with or disposed near the reflection mirror. At least one of the leads is insulated from the reflection mirror. The pair of the leads and the reflection mirror are made of a material having a high heat conductivity, respectively, so as to have a sufficient heat capacity for diffusing heat radiated from the LED element.
With the reflective LED having such features, the one lead on which the LED element is mounted is contacted with or disposed near the reflection mirror. Therefore, the heat of the LED element conducts from the one lead, which is made of the material having high heat-conductivity and which has a sufficient heat capacity for diffusing the heat radiated from the LED element, to the reflection mirror, which is made of the material having high heat-conductivity and which has a sufficient heat capacity for diffusing the heat radiated from the LED element. Consequently, the heat is radiated from the entire reflection mirror. As a result, the LED has a very high heat radiation. Since one or both of the one lead and the other lead is insulated from the reflection mirror, there is no possibility that the one lead and the other lead are short-circuited via the reflection mirror.
The reflection mirror of concave shape that faces the light emitting side of the LED element has high reflectance and high external radiation efficiency. The reflection mirror has many choices in design of light radiation property such as light distribution property. Therefore, the LED can realize high light intensity.
Since the reflection surface is made of the material having high heat-conductivity, it has durability against a temperature change and does not lose its function as the reflection mirror due to generation of wrinkles caused by the temperature change that has been found in a reflection mirror having a metal vapor-deposited on a resin surface. Therefore, the LED can be processed in a reflow furnace for surface mounting and can be used as surface mounting parts without any limits. Consequently, the LED is suitable as reflective LEDs that are mounted in a great amount. Moreover, in such structure of the reflective LED, it is unnecessary to provide an extra space for lead extracting portions, so that the LED is suitable for miniaturization, too.
A reflective LED may further comprise a light transmitting material for encapsulation. The light transmitting material encapsulates the LED element, part of the pair of the leads and the reflection mirror by molding so as to form the reflection portion.
With the reflective LED having such features, the LED element is encapsulated by the light transmitting material. Therefore, a light output from the LED element becomes twice as large as one that outputs the light directly to the air. Consequently, the LED can enlarge quantity of light of the external radiation. Since the LED element is encapsulated, it is prevented from degradation due to moisture. Therefore, the LED has high reliability. The radiation portion is made by molding while the LED element, part of the leads and the reflection mirror are encapsulated by the light transmitting material. Therefore, a surface roughness of the radiation portion becomes an optical level by mirror-polishing an inner wall surface of an encapsulating mold and is formed as an optical surface. Consequently, there is no scattering at an interface of the radiation portion. The light reflected at the reflection mirror is radiated from the radiation portion as it is with high external radiation efficiency.
Moreover, a final step is only a step for setting the members in the metal mold and encapsulating them by the resin. Therefore, the LED can be easily manufactured by use of existing production machines. Consequently, mass-production of the reflective LED is achieved.
A reflective LED may further comprise a heat-conducting portion formed at a border portion of the reflection mirror so as to conduct heat from the one of the leads.
If the heat-conducting portion is formed at the border portion of the reflection mirror, a contacted or a faced area of the one lead with the LED element mounted relative to the reflection mirror increases. Therefore, the heat of the LED element can be conducted to the reflection mirror more effectively via the one lead. Consequently, the LED becomes a reflective LED that is more excellent in the heat conductivity.
In a reflective LED, the heat-conducting portion may comprise a flat marginal portion of a ring shape integrally formed along an outer circumferential edge of the reflection mirror so as to protrude outward in a flange shape.
In a reflective LED, the heat-conducting portion may comprise protrusions of a flat plate shape protruding outward only from positions corresponding to the leads in an outer circumferential edge of the reflection mirror.
In a reflective LED, the pair of the leads and the reflection mirror may be made of a metal plate, respectively.
The metal plate has high heat conductivity and excellent workability. Therefore, it is possible to easily fabricate the reflection mirror of concave shape. Since the heat of the LED element is conducted from the one lead to the reflection mirror both made of the metal plate, the heat can be radiated from the entire reflection mirror. Therefore, the LED becomes a reflective LED that is very excellent in heat radiation.
In a reflective LED, the reflection mirror may be made of an aluminum plate.
The aluminum plate is a material that is easy to be pressed. Therefore, it is possible to easily fabricate the reflection mirror by pressing. Moreover, it is possible to easily obtain aluminum plate having very high linear reflectance. Therefore, it is possible to easily fabricate the reflection mirror having high reflectance. Since the aluminum plate has high heat conductivity, the heat of the LED element is conducted from the one lead to the reflection mirror both made of the aluminum plate, so that the heat can be radiated from the entire reflection mirror. Therefore, the LED becomes a reflective LED that is very excellent in heat radiation. Moreover, the aluminum has high reflectance in a wavelength zone from a visible light to an ultraviolet light. Therefore, if it is made into the reflection mirror, there is no need for plating treatment. Particularly, in case an ultraviolet LED element is used as the LED element, the silver has very low reflectance in a zone of the ultraviolet rays. Therefore, the reflection mirror of the aluminum plate can obtain high reflectance for the ultraviolet rays that cannot be obtained by the widely used silver plating.
In a reflective LED, the pair of the leads may be disposed near the reflection mirror. The reflective LED further comprises an insulating sheet material having a ring shape corresponding to the flat marginal portion of the reflection mirror and interposed between the pair of the leads and the flat marginal portion of the reflection mirror so as to insulate the pair of the leads and the reflection mirror, respectively.
In a reflective LED, the one of the leads may be contacted with the reflection mirror. The other of the leads is disposed away from the reflection mirror via one of a cut-away portion formed at a position of the reflection mirror facing the other of the lead, a dent formed at a position of the reflection mirror facing the other of the lead and a bridging portion formed at a position of the reflection mirror facing the other of the lead, so that the other of the leads is insulated from the reflection mirror.
In a reflective LED, the reflection mirror may have a light transmitting insulating treatment provided on a surface and the pair of the leads are contacted with the reflection mirror.
Specifically, in the reflective LED of the invention, the reflection mirror is provided with the light transmitting insulating treatment (oxidation treatment) on the surface of the metal plate. The surface of the reflection mirror can be given insulation without decreasing the reflectance of the reflection mirror by forming the insulating metallic oxide on the surface. Therefore, even if the one lead and the other lead are both contacted with the reflection mirror, the one lead and the other lead are never short-circuited. Consequently, fabrication of the reflective LED using the metal reflection mirror becomes easy. Moreover, the one lead can be contacted with the reflection mirror, so that the heat conductivity improves and the LED becomes more excellent in the hear radiation.
In a reflective LED, the pair of the leads may be contacted with an outer circumferential edge of the reflection mirror. The radiation portion is made of a glass plate covering an entire opening of the reflection mirror from an outside of the pair of the leads. The reflection mirror has hooking claws at the outer circumferential edge so as to hook an outer surface of an outer circumferential edge portion of the reflection mirror through the hooking claws, thereby holding and assembling the pair of the leads between the outer circumferential edge and the glass plate.
In a reflective LED, the reflection mirror may have a reflection surface formed on an alumina and a reflection layer vapor-deposited on the reflection surface so as to have a hollow inside space. The reflection mirror has recesses formed on an outer circumference for accommodating the pair of the leads. The pair of the leads are fitted in the recesses of the reflection mirror, respectively, and at least the one of the leads is contacted with the reflection mirror via the dent.
According to a second aspect of the invention, there is provided a reflective optical device comprising: a solid-state optical element, a lead, an encapsulating material and a reflection member. The solid-state optical element is mounted on the lead. The reflection member has a reflection mirror formed thereon. The reflection mirror is disposed at a position facing the solid-state optical element. The encapsulating material encapsulates the solid-state optical element, part of the lead and the reflection mirror so that a light radiation surface and/or a light incident surface is formed at a back of the solid-state optical element. The lead is extracted from one side of the encapsulating material to define an external terminal.
With the reflective optical device having such structure, the lead on which the solid-state optical element is mounted so as to face the reflection mirror is extracted as the external terminal. Therefore, encapsulation of the solid-state optical element, part of the lead and the reflection member as well as molding of the radiation surface can be performed by the potting mold. Consequently, there are many choices of the encapsulating materials to be used. Moreover, an encapsulating material that is hard to be yellowed can be selected and used. Since the potting mold does not need high accuracy, it is easy to fabricate the metal mold. Therefore, the optical device is excellent in mass-productivity. Furthermore, since the solid-state optical element is disposed so as to face the reflection mirror, the reflective optical device has high light condensation/radiation efficiency or high light incident efficiency and little dislocation of the axis.
Since the reflection mirror is not made by vapor-deposition, it has durability against a temperature change and does not lose its function as the reflection mirror due to generation of wrinkles caused by the temperature change that has been found in a reflection mirror having a metal vapor-deposited on a resin surface. Therefore, the optical device can be processed in a reflow furnace for surface mounting and can be used as surface mounting parts without any limits. Consequently, the optical device is suitable as reflective optical devices that are mounted in a great amount. Moreover, in such structure of the reflective optical device, it is unnecessary to provide an extra space for lead extracting portions, so that the optical device is suitable for miniaturization, too.
As described above, the reflective optical device has high light condensation/radiation efficiency or high light incident efficiency and little dislocation of the axis. Moreover, the optical device can be processed in the reflow furnace and miniatured. Furthermore, it is easy to fabricate the metal mold and the encapsulating a material resistant to yellowing can be used. In addition, the optical device is excellent in mass-productivity.
In a reflective optical device, the reflection member may be made of a metal.
Accordingly, since the reflection mirror is made of the metal, it has durability against a temperature change and does not lose its function as the reflection mirror due to generation of wrinkles caused by the temperature change that has been found in a reflection mirror having a metal vapor-deposited on a resin surface. Therefore, the optical device can be processed in a reflow furnace for surface mounting and can be used as surface mounting parts without any limits. Consequently, the optical device is suitable as reflective optical devices that are mounted in a great amount. Moreover, in such structure of the reflective optical device, it is unnecessary to provide an extra space for lead extracting portions, so that the optical device is suitable for miniaturization, too.
Since the reflection member is made of the metal, there is no possibility that the reflection mirror is deformed due to heat at the time of encapsulation as in the case of a reflection member made of a resin. Moreover, there is no possibility that the reflection member hurts the lead when secured to the lead as in the case of a reflection member made of ceramics. Thus, the reflection member has good compatibility with the lead.
In a reflective optical device, the reflection member may be made of a metal plate.
Accordingly, successive plural reflection mirrors can be fabricated at once by pressing the metal plate, thereby improving mass-productivity. Since the reflection mirror is made of the metal plate, it has durability against a temperature change and does not lose its function as the reflection mirror due to generation of wrinkles caused by the temperature change that has been found in a reflection mirror having a metal vapor-deposited on a resin surface. Therefore, the optical device can be processed in a reflow furnace for surface mounting and can be used as surface mounting parts without any limits. Consequently, the optical device is suitable as reflective optical devices that are mounted in a great amount. Moreover, it is possible to easily manufacture an optical device of different specification of light distribution only by changing a punch for forming the reflection mirror. There is no need to fabricate a new metal mold each time.
In a reflective optical device, the reflection mirror may be made only of the reflection member itself.
Accordingly, the reflection mirror can be formed only by pressing an aluminum plate having high linear reflectance as it is, for example. Therefore, the manufacturing process is shortened and the reflective optical device can be manufactured in short time as compared with the case in which a brass reflection member is pressed and plated with silver so as to form a reflection mirror, for example.
In a reflective optical device, the reflection mirror of the reflection member may have a linear reflectance of about 65% or more.
As materials having such high linear reflectance, there are exemplified a coined rolled aluminum, a high-luminance aluminum that has been mirror-finished at the time of rolling, a material with a silver plating to heighten the linear reflectance, etc. With the reflection mirror having such high linear reflectance, scattering of the light is restrained to a very low level at a reflecting point in case of a reflective LED. Therefore, it is possible to provide high light condensation factor. Particularly, if the LED element is encapsulated by the light transmitting resin, the light scattered at the reflection surface is further refracted when radiated from the light radiation surface, thereby increasing scattering rate. Therefore, it is important to keep the linear reflectance high. In case of a reflective PD or a reflective PT, scattering of the incident light is restrained, so that a photo-detecting factor is heightened more. As described above, if the linear reflectance of the reflection mirror is about 65% or more, there is provided a reflective optical device that has superior property.
In a reflective optical device, the lead may be extracted to a side of the encapsulating material facing a side surface of the solid-state optical element.
Accordingly, an outline of a member to be made by potting mold becomes thin. Moreover, it is possible to make thin an inside space of a mold for the potting mold. Therefore, the potting mold becomes easy and an amount of used encapsulating resin can be saved to a large degree.
In a reflective optical device, the lead may be extracted to a side of the encapsulating material facing a back surface of the solid-state optical element.
Accordingly, the optical device becomes ready for surface mounting only by bending the lead along the bottom surface of the encapsulating material (corresponding to a front surface of the encapsulating material at the time of potting mold) after the lead and the reflection member are encapsulated by potting mold. Thus, there is provided a reflective optical device that is easy to be surface-mounted.
In a reflective optical device, the reflection member may have a reflection member support at a leading end side that is an opposite side to an extracting side of the lead. The reflection member is connected to the reflection member to support the reflection member. A leading end side of the lead is extended so as to overlap with the reflection member support. The leading end side of the lead and the reflection member support are tightly contacted and encapsulated by the encapsulating material.
Accordingly, the leading end portion of the lead is pressed to the reflection member support. Thereby, the lead and the border of the reflection mirror are tightly contacted, so that the solid-state optical element is more surely and strongly fixed at the center of the reflection mirror. Thus, there is provided a reflective optical device that can fix the solid-state optical element more surely and strongly at the center of the reflection mirror.
According to a third aspect of the invention, there is provided a manufacturing method of a reflective optical device, comprising the steps of: fixing a lead frame and a reflection member in a fixed positional relationship, the lead frame having a lead while the lead having a solid-state optical element mounted thereon, and the reflection member having a reflection mirror; and encapsulating the solid-state optical element, the reflection mirror and part of the lead frame in a concave mold by filling the concave mold with an encapsulating material, while molding an optical radiation surface and/or optical incident surface at a back side of the solid-state optical element.
According to the manufacturing method by such potting mold, there is provided a reflective optical device that has high light condensation/radiation efficiency or high light incident efficiency while having little dislocation of an axis. Moreover, if the solid-state optical element is retained at a fixed position (center) relative to the reflection mirror, an upward or downward dislocation thereof at the time of potting mold never affects dislocation of an axis. With the potting mold, the metal mold does not require high accuracy and it is enough to mold only the light radiation surface and/or the light incident surface. Therefore, it is easy to fabricate the metal mold. Since there are many choices in selecting the encapsulating materials in case of the potting mold, the life of the reflective optical device becomes long if using an encapsulating a material resistant to yellowing. If a reflection mirror having durability against a temperature change, it does not lose its function as the reflection mirror due to generation of wrinkles caused by the temperature change that has been found in a reflection mirror having a metal vapor-deposited on a resin surface. Therefore, the optical device can be processed in a reflow furnace for surface mounting and can be used as surface mounting parts without any limits. Consequently, the optical device is suitable as reflective optical devices that are mounted in a great amount. Moreover, in such structure of the reflective optical device, it is unnecessary to provide an extra space for lead extracting portions, so that the optical device is suitable for miniaturization, too.
As described above, there is provided a manufacturing method for the reflective optical device that has high light condensation/radiation efficiency or high light incident efficiency and little dislocation of the axis. Moreover, there is provided a manufacturing method for the optical device that can be processed in the reflow furnace and miniatured. Furthermore, there is provided a manufacturing method for the optical device by which it is easy to fabricate the metal mold and which the encapsulating a material resistant to yellowing can be used.
In a manufacturing method of a reflective optical device, a multiplicity of the leads may be successively formed on the lead frame. A multiplicity of the reflection mirrors are successively formed on the reflection member. The solid-state optical element is mounted on each of the leads.
Accordingly, many pairs of the leads with the solid-state optical elements mounted and the reflection mirrors are arranged easily in a large number by laying the lead frame and the reflection member on each other. On the other hand, a metal mold for the potting mold is easy to be fabricated. It is also easy to fabricate many molds in accordance with an arranged distance of the leads and the reflection mirrors. Then, the same number of the pairs of the leads and the reflection mirrors and the molds for the potting mold are prepared. Thereafter, each pair of the lead and the reflection mirror is set in each mold. The mold is filled in each mold. Then, they are passed through a heating zone to be hardened. Thereafter, the leads and the reflection mirrors are taken out of the molds. Thus, there are manufactured many reflective optical devices.
As described above, there is provided a manufacturing method for the reflective optical devices that can be easily mass-produced while having superior characteristics.
In a manufacturing method of a reflective optical device, the reflection member may have a reflection member support at a leading end. A leading end side of the lead is extended so as to be overlap with the reflection member support. An inside shape of the mold is tapered toward a leading end of the mold.
Accordingly, the leading end portion of the lead is pressed against the reflection member support as the fixed lead and the reflection mirror are inserted into the mold. Thereby, the lead is tightly contacted with the border of the reflection mirror. Then, the solid-state optical element is secured more surely and strongly to the center of the reflection mirror.
As described above, there is provided a manufacturing method for the reflective optical devices that can easily secure the solid-state optical element more surely and strongly at the center of the reflection mirror.
According to a fourth aspect of the invention, there is provided a manufacturing method of a reflective optical device. The reflective optical device comprises a solid-state optical element, a lead, an encapsulating material and a reflection member. The manufacturing method comprises the steps of: mounting the solid-state optical element on the lead; laying a lead frame supporting the lead and a reflection member having the reflection mirror on each other so that at least part of the lead frame around a portion of the lead on which the solid-state optical element is mounted and at least part of the reflection member around the reflection mirror are overlapped with each other and so that an overlapped part reaches a surrounding of the reflection mirror about the reflection mirror; and holding at least part of the overlapped portion of the lead frame and the reflection member between a pair of molds so as to dispose the reflection mirror and the lead in a cavity formed in the molds, thereby encapsulating the reflection mirror and the lead by an encapsulating material.
With the manufacturing method, the solid-state optical element mounted on the lead can be located so as to face the reflection mirror. Therefore, the reflective optical device has high light condensation/radiation efficiency or high light incident efficiency as well as little dislocation of the axis. Since the reflection surface is formed by the metal plate having the reflection mirror, it has durability against a temperature change and a physical contact and does not lose its function as the reflection mirror due to generation of wrinkles caused by the temperature change that has been found in a reflection mirror having a metal vapor-deposited on a resin surface. Therefore, the optical device can be processed in a reflow furnace for surface mounting and can be used as surface mounting parts without any limits. Consequently, the optical device is suitable as reflective optical devices that are mounted in a great amount. Moreover, in such structure of the reflective optical device, it is unnecessary to provide an extra space for lead extracting portions, so that the optical device is suitable for miniaturization, too. Furthermore, it can deal with change of light distribution property only by changing the shape of the reflection surface and there is no need to fabricate a new metal mold each time.
As described above, there is provided a manufacturing method of the reflective optical device that has high light condensation/radiation efficiency or high light incident efficiency and little dislocation of the axis. Moreover, the optical device can be processed in the reflow furnace and miniatured. Furthermore, it is unnecessary to renew the metal mold each time the light distribution property is changed so that the manufacturing method is excellent in mass-productivity.
According to a fifth aspect of the invention, there is provided a manufacturing method of a reflective optical device, comprising the steps of: mounting a solid-state optical element on a lead; mounting the lead supported on a lead frame on a reflection mirror provided on a reflection member so that the solid-state optical element faces the reflection mirror; and holding the reflection member and the lead frame between metal molds and encapsulating the reflection member and the lead frame by an encapsulating resin after deforming a reflection mirror support, which is provided on the reflection member so as to extend outward from the reflection mirror, at a middle position thereof to a same height as the lead so that a portion of the reflection member corresponding to the reflection mirror is disposed within a thickness of a portion of the lead frame corresponding to the reflection mirror.
In the manufacturing method, since the reflection mirror support is deformed by bending or the like so as to come to the same height as the lead, it is sufficient to seal a circumference of the cavity with a thickness of one plate. Therefore, the seal is improved and the resin leakage is minimized or eliminated. Consequently, the metal mold can be fabricated easily. Moreover, the plate-shaped burr has a thickness of one plate, so that the burr can be easily removed after molding and there is no possibility that crack is generated at a resin sealed portion at the time of removing the burrs.
Since the solid-state optical element mounted on the lead can be located so as to face the reflection mirror, the reflective optical device has high light condensation/radiation efficiency or high light incident efficiency as well as little dislocation of the axis. Since the reflection surface is formed by the reflection mirror, it has durability against a temperature change and a physical contact and does not lose its function as the reflection mirror due to generation of wrinkles caused by the temperature change that has been found in a reflection mirror having a metal vapor-deposited on a resin surface. Therefore, the optical device can be processed in a reflow furnace for surface mounting and can be used as surface mounting parts without any limits. Consequently, the optical device is suitable as reflective optical devices that are mounted in a great amount. Moreover, in such structure of the reflective optical device, it is unnecessary to provide an extra space for lead extracting portions, so that the optical device is suitable for miniaturization, too. Furthermore, it can deal with change of light distribution property only by changing the shape of the reflection surface and there is no need to fabricate a new metal mold each time.
As described above, there is provided a manufacturing method of the reflective optical device that improves the sealing property for the cavity at the time of molding and that has high light condensation/radiation efficiency or high light incident efficiency and little dislocation of the axis. Moreover, the optical device can be processed in the reflow furnace and miniatured. Furthermore, it is unnecessary to renew the metal mold each time the light distribution property is changed so that the manufacturing method is excellent in mass-productivity.
According to a sixth aspect of the invention, there is provided a manufacturing method of a reflective optical device, comprising the steps of: mounting a solid-state optical element on a lead; mounting the lead supported on a lead frame on a reflection mirror provided on a reflection member so that the solid-state optical element faces the reflection mirror; and holding the reflection member and the lead frame between metal molds and encapsulating the reflection member and the lead frame by an encapsulating resin after deforming the lead to a same height as a reflection mirror support, which is provided on the reflection member so as to extend outward from the reflection mirror, so that a portion of the lead frame corresponding to the reflection mirror is disposed within a thickness of a portion of the reflection member corresponding to the reflection mirror.
In this invention, contrary to the fifth aspect of the invention, the lead is deformed so as to come to the same height as the reflection mirror support. Thereby, it is sufficient to seal a circumference of the cavity with a thickness of one plate. Therefore, sealing property improves and leakage of the resin lessens extremely. Consequently, the metal mold can be fabricated easily. Moreover, the plate-shaped burr has a thickness of one plate, so that the burr can be easily removed after molding and there is no possibility that crack is generated at a resin sealed portion at the time of removing the burrs.
Since the solid-state optical element mounted on the lead can be located so as to face the reflection mirror, the reflective optical device has high light condensation/radiation efficiency or high light incident efficiency as well as little dislocation of the axis. Since the reflection surface is formed by the reflection mirror, it has durability against a temperature change and a physical contact and does not lose its function as the reflection mirror due to generation of wrinkles caused by the temperature change that has been found in a reflection mirror having a metal vapor-deposited on a resin surface. Therefore, the optical device can be processed in a reflow furnace for surface mounting and can be used as surface mounting parts without any limits. Consequently, the optical device is suitable as reflective optical devices that are mounted in a great amount. Moreover, in such structure of the reflective optical device, it is unnecessary to provide an extra space for lead extracting portions, so that the optical device is suitable for miniaturization, too. Furthermore, it can deal with change of light distribution property only by changing the shape of the reflection surface and there is no need to fabricate a new metal mold each time.
As described above, there is provided a manufacturing method of the reflective optical device that improves the sealing property for the cavity at the time of molding and that has high light condensation/radiation efficiency or high light incident efficiency and little dislocation of the axis. Moreover, the optical device can be processed in the reflow furnace and miniatured. Furthermore, it is unnecessary to renew the metal mold each time the light distribution property is changed so that the manufacturing method is excellent in mass-productivity.
According to a seventh aspect of the invention, there is provided a reflective optical device comprising: a solid-state optical element, a lead, an encapsulating material and a reflection mirror. The solid-state optical element is mounted on the lead. The reflection member has a reflection mirror formed thereon. The reflection mirror is disposed at a position facing the solid-state optical element. The reflection mirror has a border portion disposed within a height of a rear surface of the lead from a surface of the lead on which the solid-state optical element is mounted. The encapsulating material encapsulates the solid-state optical element and the reflection mirror so as to form a light radiation surface and/or a light incident surface at a back of the solid-state optical element.
In the reflective optical device, the lead and the reflection mirror support are not overlapped at a mating face of the cavity of the metal mold as in the fourth aspect of the invention. They are located at the same plane. Therefore, it is sufficient to seal a circumference of the cavity with a thickness of one plate. Therefore, sealing property improves and leakage of the resin lessens extremely. Consequently, the metal mold can be fabricated easily. Moreover, the plate-shaped burr has a thickness of one plate, so that the burr can be easily removed after molding and there is no possibility that crack is generated at a resin sealed portion at the time of removing the burrs.
If the reflection mirror is located so as to face the solid-state optical element mounted on the lead, the reflective optical device has high light condensation/radiation efficiency or high light incident efficiency as well as little dislocation of the axis. Since the reflection surface is formed by the reflection mirror, it has durability against a temperature change and a physical contact and does not lose its function as the reflection mirror due to generation of wrinkles caused by the temperature change that has been found in a reflection mirror having a metal vapor-deposited on a resin surface. Therefore, the optical device can be processed in a reflow furnace for surface mounting and can be used as surface mounting parts without any limits. Consequently, the optical device is suitable as reflective optical devices that are mounted in a great amount. Moreover, in such structure of the reflective optical device, it is unnecessary to provide an extra space for lead extracting portions, so that the optical device is suitable for miniaturization, too. Furthermore, it can deal with change of light distribution property only by changing the shape of the reflection surface and there is no need to fabricate a new metal mold each time.
Since the border portion of the reflection mirror is located within the height of the rear surface of the lead from the surface of the lead on which the solid-state optical element is mounted, a solid angle of the reflection mirror becomes 2xcfx80 steradian or more. Therefore, quantity of light that is emitted from the solid-state optical element via the reflection mirror or that enters the solid-state optical element is enlarged.
As described above, there is provided a reflective optical device that has high light condensation/radiation efficiency or high light incident efficiency and little dislocation of the axis. Moreover, the optical device can be processed in the reflow furnace and miniatured. Furthermore, it is unnecessary to renew the metal mold each time the light distribution property is changed so that the manufacturing method is excellent in mass-productivity.
Further objects and advantages of the invention will be apparent from the following description, reference being had to the accompanying drawings, wherein preferred embodiments of the invention are clearly shown.